Electroencephalography is a safe, noninvasive technique for monitoring neonatal brain function. Acute and long-term EEG monitoring of infants has clinical utility for evaluating the effects of hypoxic ischemic insults and detecting the presence of epileptic activity. The information available in neonatal EEG can be greatly enhanced by using an adequate number of electrodes to accurately map the spatial distribution of the EEG without spatial aliasing. The Geodesic Neonatal EEG Brain Monitor will be designed from experimental studies and theoretical simulations of the required sampling density for scalp potentials on the infant head. Dense Array EEG methods will be developed that incorporate the unique features of infant skull anatomy to estimate the potentials in the brain of the infant. The Geodesic Neonatal EEG Brain Monitor system will be adapted for a variety of clinical uses, initially focusing on monitoring brain function in sleep in the Neonatal Intensive Care Unit (NICU). This monitoring will examine both normal and pathological sleep states of the neonate, providing information on the maturation of arousal control in preterm and full term infants that may be important in understanding sudden infant death syndrome. PROPOSED COMMERCIAL APPLICATION: Behavioral outcome studies indicate that brain function is often at risk in the neonatal intensive care unit. An inexpensive, high-resolution neonatal brain state monitor could guide medical management to support brain health and therefore improve neurological and psychological outcome in many infants.